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Help! Front disk brake conversion issues

B5WannaBee

B5WannaBee

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Feb 23, 2020
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Location
Milton, Fl
Hello from Milton Fl!
I have a 1970 Coronet 440 with a 318. She was a little squirly on the toad due to some suspension issues and since my daughter was driving it I wanted to make it as safe as possible. I ripped out all of the suspension and put in all new stuff. While I had it all apart I decided to move into uncharted territory for me and do a front manual drum to disk upgrade. Keep in mind the m new at this... I have only done the disks and haven’t changed out the MC / PV. I have bled the brakes with the original MC and PV on it but the pedal goes to the floor without any resistance or braking at all. Do I need a new MC PV?

08687A97-AA9B-46C2-B16E-4176EA176E14.jpeg BEAE2B6C-7C45-4E2D-9A83-313F8CBFBD0B.jpeg
 
Does it need to be hooked up to a new PV or power booster, and can I run it manually?
 
You should also swap sides on the calipers. The bleeder should be at the top so air bleeds out. When they are on the bottom an air pocket can stay in the calipers.
 
Manuel brakes are just that. No power anything.Did you bleed them out properly?? You need to swap sides with the calipers REbleed and let us know the results.
 
With the calipers mounted the way you have them now, it will be impossible to get all the air out. That is why your peddle is going to the floor. Get a mc like Jim posted above with a 15/16 or 1 1/32 bore and a new prop valve. Be sure to bench bleed the cylinder before installing in the car. Cass aka Dr. Diff is a good source for these parts.
 
Last edited:
After you get your caliper position sorted out, make sure your hoses don't twist or rub or over extend etc. while turning the wheel and moving the suspension.
 
Thanks everyone! I’ll be working on it this week. I’ll get in touch with Dr Diff.
 
T2R9 said:
You should also swap sides on the calipers. The bleeder should be at the top so air bleeds out. When they are on the bottom an air pocket can stay in the calipers.
Click to expand...
good catch if he swaps the caliper and re-bleeds might work as is. i have seen experienced tech make this mistake.
 
When mounted on the car, the bleeder valve should be at the highest possible point. The two things you absolutely need to do are:
  • swap calipers (left to right sides)
  • replace master cylinder with a disc brake specific unit (as pictured above)
 
I’ve searched for Dr Diff. Any one have his number handy? Does he have a website?
 
welcome

maybe post this in the Brakes Steering & Suspension forum here

this is just the welcome wagon
 
I’m doing the Dr Diff disc brake conversion right now. His calipers have two bleeders on each to allow them to be mounted front or back of the spindle depending on your clearance needs.
 
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